Enantioselective Allylation of Alkenyl Boronates Promotes a 1,2-Metalate Rearrangement with 1,3-Diastereocontrol
作者:Colton R. Davis、Irungu K. Luvaga、Joseph M. Ready
DOI:10.1021/jacs.1c01242
日期:2021.4.7
Alkenyl boronates add to Ir(π-allyl) intermediates with high enantioselectivity. A 1,2-metalate shift forms a second C–C bond and sets a 1,3-stereochemical relationship. The three-component coupling provides tertiary boronic esters that can undergo multiple additional functionalizations. An extension to trisubstituted olefins sets three contiguous stereocenters.
Two-Carbon Ring Expansion of 1-Indanones via Insertion of Ethylene into Carbon–Carbon Bonds
作者:Ying Xia、Shusuke Ochi、Guangbin Dong
DOI:10.1021/jacs.9b07445
日期:2019.8.21
A rhodium-catalyzed direct insertion of ethylene into a relatively unstrained carbon-carbon bond in 1-indanones is reported, which provides a two-carbon ring-expansion strategy for preparing seven-membered cyclic ketones. As many 1-indanones are commercially available and ethylene is inexpensive, this strategy simplifies synthesis of benzocycloheptenones that are valuable synthetic intermediates for
Hybrid Metal/Organo Relay Catalysis Enables Enynes To Be Latent Dienes for Asymmetric Diels–Alder Reaction
作者:Zhi-Yong Han、Dian-Feng Chen、Ya-Yi Wang、Rui Guo、Pu-Sheng Wang、Chao Wang、Liu-Zhu Gong
DOI:10.1021/ja3007148
日期:2012.4.18
to serve as latent 1,3-silyloxydienes capable of participating in the first cascadehydrosiloxylation of an enynyl silanol/asymmetric Diels-Alder reaction. A variety of polycyclic compounds bearing multistereogenic centers were obtained in high yields and excellent enantioselectivities from the relaycatalyticcascadereaction between (2-(but-3-en-1-ynyl)phenyl) silanols and quinones catalyzed by the
Readily available from esters or ketones, cyclopropanols are inclined to undergo diverse ring-opening transformations. Their one-electron oxidation is a conventional way to β-carbonyl radicals. However, despite this fact, their application as a coupling partner in dual photoredox and nickel-catalyzed reactions with organic halides remains underdeveloped. Here, we report that the Ti(OiPr)4 additive
环丙醇很容易从酯或酮中获得,倾向于进行各种开环转化。它们的单电子氧化是β-羰基自由基的常规方式。然而,尽管如此,它们作为偶联伙伴在与有机卤化物的双重光氧化还原和镍催化反应中的应用仍然不成熟。在这里,我们报告了 Ti(O i Pr) 4添加剂使这种难以捉摸的与芳基溴和烯基溴的交叉偶联成为可能,从而产生 β 取代的酮。
THE CYANATION OF VINYL HALIDES CATALYZED BY NICKEL(0) COMPLEX GENERATED IN SITU
Nickel(0) species generated in situ from NiBr2(PPh3)2–Zn–PPh3catalyzed the formation of unsaturated nitriles from vinylhalides and potassium cyanide. The reaction proceeded under very mild conditions and was stereoselective.